They have to schedule time on the DSN (Deep Space Network) to communicate with the spacecraft. Time on a global satellite tracking network is not cheap. There are probably additional costs for people and support services.
Keeping all of the sensitive bits of a satellite within a reasonable temperature range is tricky. You have electronics modules producing heat that must be radiated into space. The exterior of the spacecraft has to cope with the temperature extremes of sunlight and shade. You don't want the batteries to freeze. Some parts of the spacecraft might be damaged if they are allowed to get too cold.
When the IBM PC was introduced, there were second sources for almost all of the chips in the machine. Back then, engineers demanded second sources for ICs. Intel didn't stop signing agreements for second sources until years later.
Everything you know is wrong
on
Review: U-571
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· Score: 2
The Poles (Marian Rejewski et al) cracked the Enigma code. The British exploited and expanded on their work.
It gets back to what is considered a threat. Embarassing someone, or ostracizing someone is not considered a threat.
Suppose, purely for the sake of argument, that you are a frequent customer of an adult book store. You also live in a small town in Utah. Someone gives me a photograph of you entering the book store. I make 100 copies of the photograph and distribute them to your neighbors.
Your neighbors are horrified, stop talking to you and give you evil looks. Have I committed a crime?
Go to some random college campus and see how people are treated when their views don't conform to the prevailing orthodoxy. Print the wrong thing in a student newspaper and the copies of the newspaper will be stolen or destroyed. Invite the wrong speaker to the campus and see the heckler's veto, death threats and spineless capitulation from the college administration. See how student funds are allocated to campus groups based on ideology. Watch academic freedom vanish when a professor is accused of thought crimes.
See this op-ed column to see what passes for tolerance on some campuses.
What threat? I've looked at the site and I didn't see any threats, just information that makes pro-choice advocates very uncomfortable. What if I put up posters all over town with the pictures, names, addresses and biographies of NAZI war criminals? I'm sure that the people pictured on the posters would be very upset.
I'm pro-death (pro-choice and support capital punishment), but I don't like the way many pro-choice groups try to ignore the Bill of Rights when pro-life groups exercise their constitutional rights.
NASA funding has been in a slow decline for decades. During the Apollo program, NASA had a lot more money to spend on the people and equipment needed to do the job right. Today, the agency is in a slow-motion implosion. Many people are retiring or are being forced out by budget cuts. Very few new people are being hired. There is little money for developing new technology or replacing old equipment. Faster, cheaper, better, pick two.
Amateur Radio has a frequency allocation at 2390-2450 MHz. This overlaps the ISM band that is used with 802.11b and other unlicensed users. Unlicensed users must accept interference from licensed users and must not cause interference to licensed users.
I'm currently updating some software for a NASA computer system that was designed and built in the late 1970s. The computer is a custom design built out of wire-wrapped 7400 series TTL chips and 2102 memory chips. These were mass-market chips when the system was designed. They have become increasingly difficult to find as the years go by. The computer originally used a DEC LSI-11 with RX01 8" floppy disk drives as its console and program loading device. Floppy disk drives wear out and it became
impossible to find replacement parts for them.
The computer can't be easily replaced with a modern system. There is a large library of applications, in assembly language, that would have to be rewritten. It isn't a general purpose computer. Its architecture was carefully designed and optimized for a narrow task, and it does that task better than any modern general purpose computer. Duplicating its functionality with modern technology would cost a huge amount of money.
Exabyte can't prevent people from using the word exabyte. Many trademarks are composed of common words. For example, Coke, Mountain Dew, Java, Sun, Ford, Mercury, Fiat, Jaguar.
To hell with cameras, I want 500 megawatt lasers installed at all intersections. You can run a red light, once.
I've been driving for many years without a ticket for a moving violation or a serious accident. It is not that difficult to obey the law and drive safely. Most of the problem is people's attitude towards driving. The road is not a race track, traffic signals and signs are not friendly suggestions. Driving like a jerk does not make you into a real man/woman.
The idea behind forcing a BSOD or other fatal error is to prevent the user from processing corrupted data. It is telling you that your computer is broken and to get it fixed.
With ECC, and a properly written operating system, the damage can be handled in a more subtle way. Correctable errors are logged for later maintenance. Uncorrectable errors only kill the application they occur in, if the address of the error is in an application's address space. The operating system can keep a list of memory pages that have generated errors, and not allocate those pages for use in the future, sort of like a bad block list on a hard disk.
Re:ECC where useful / speed compromise
on
To ECC Or Not To ECC?
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· Score: 4, Informative
ECC protection of main memory is distinct from ECC protection of CPU cache memory. They are independent. You can have ECC main memory with or without ECC cache. On PCs, the ECC encoder/decoder for cache is on the CPU chip, the ECC encoder/decoder for main memory is part of the chipset.
I believe ECC is worth having, even if you are not using the computer to run "mission critical" tasks. Memory problems on a computer without parity or ECC can be very difficult to diagnose. The symptoms may look like a flakey operating system or application, not a hardware problem. I had one computer that would only fail when someone ran the FORTRAN compiler. The symptoms looked exactly like a bug in the FORTRAN compiler. It turned out that one of the DRAM chips had a pattern sensitivity problem that was triggered by the image of the FORTRAN compiler.
These kinds of problems can be difficult to detect and fix without hardware support. The memory diagnostics in the power-on self-test in the BIOS will detect hard errors, but not more subtle errors.
Re:I can't understand ECC - specifics
on
To ECC Or Not To ECC?
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· Score: 4, Informative
You want "Checking, Correction w/ Scrubbing".
Scrubbing detects and corrects memory errors that are in memory addresses that are idle. This prevents correctable errors from turning into uncorrectable errors in sections of memory that are infrequently accessed by the CPU.
The Internet is not the Internet without end-to-end transparency and addressability. Any randomly selected node must be able to send and receive packets with another randomly selected node.
Anything that prevents this, NAT, DHCP with static DNS, "transparent" proxies, draconian firewalls or usage policies, is bad. Unfortunately, many Internet users are second-class citizens, limited by technology or corporate policy to the status of "information consumers".
You may have given them the right to make inspections or audits when you signed a contract. My local cable company has a clause for this in their service agreement. A software license may also include language that permits audits.
I think I've already seen the indestructible sandwich, in an English pub. I made the mistake of buying one. It tasted like left-over emergency rations from World War II.
In one project that I worked on, the Courier worked much better than the Sportster over impaired international telephone lines. Plus, the Courier had more features, more reliable hardware and better documentation.
$300 isn't excessive for commercial grade equipment. The Courier is a well-designed modem. I've seen people try to save a few bucks by buying a cheap modem and then waste thousands of dollars on trying to make the cheap modem work properly, only to end up tossing the cheap modems and replacing them with Couriers.
Actually I do believe that a nuclear device cannot detonate "accidentally."
That is not true. Early nuclear weapons designs had severe safety problems by modern standards. It took many years of engineering and testing to solve the problems. A Hiroshima type bomb can be made to go critical by immersing it in water. A Nagasaki type bomb can explode with a measurable nuclear yield if the high-explosive lens assembly is detonated by fire or shockwave.
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They have to schedule time on the DSN (Deep Space Network) to communicate with the spacecraft. Time on a global satellite tracking network is not cheap. There are probably additional costs for people and support services.
Keeping all of the sensitive bits of a satellite within a reasonable temperature range is tricky. You have electronics modules producing heat that must be radiated into space. The exterior of the spacecraft has to cope with the temperature extremes of sunlight and shade. You don't want the batteries to freeze. Some parts of the spacecraft might be damaged if they are allowed to get too cold.
When the IBM PC was introduced, there were second sources for almost all of the chips in the machine. Back then, engineers demanded second sources for ICs. Intel didn't stop signing agreements for second sources until years later.
The Poles (Marian Rejewski et al) cracked the Enigma code. The British exploited and expanded on their work.
Suppose, purely for the sake of argument, that you are a frequent customer of an adult book store. You also live in a small town in Utah. Someone gives me a photograph of you entering the book store. I make 100 copies of the photograph and distribute them to your neighbors. Your neighbors are horrified, stop talking to you and give you evil looks. Have I committed a crime?
See this op-ed column to see what passes for tolerance on some campuses.
I'm pro-death (pro-choice and support capital punishment), but I don't like the way many pro-choice groups try to ignore the Bill of Rights when pro-life groups exercise their constitutional rights.
If you are pro-life, or have other non-PC beliefs, forget about the Bill of Rights. I hope that the Supreme Court bitch slaps the Court of Appeals.
NASA funding has been in a slow decline for decades. During the Apollo program, NASA had a lot more money to spend on the people and equipment needed to do the job right. Today, the agency is in a slow-motion implosion. Many people are retiring or are being forced out by budget cuts. Very few new people are being hired. There is little money for developing new technology or replacing old equipment. Faster, cheaper, better, pick two.
Amateur Radio has a frequency allocation at 2390-2450 MHz. This overlaps the ISM band that is used with 802.11b and other unlicensed users. Unlicensed users must accept interference from licensed users and must not cause interference to licensed users.
That doesn't work when the 8086 is being used in an embedded system running real-time software and supporting a bunch of custom I/O circuits.
The computer can't be easily replaced with a modern system. There is a large library of applications, in assembly language, that would have to be rewritten. It isn't a general purpose computer. Its architecture was carefully designed and optimized for a narrow task, and it does that task better than any modern general purpose computer. Duplicating its functionality with modern technology would cost a huge amount of money.
Exabyte can't prevent people from using the word exabyte. Many trademarks are composed of common words. For example, Coke, Mountain Dew, Java, Sun, Ford, Mercury, Fiat, Jaguar.
I've been driving for many years without a ticket for a moving violation or a serious accident. It is not that difficult to obey the law and drive safely. Most of the problem is people's attitude towards driving. The road is not a race track, traffic signals and signs are not friendly suggestions. Driving like a jerk does not make you into a real man/woman.
It's too late for 2002, but in many areas you can get Coke made with real sugar during Passover. Look for the "kosher for Passover" markings.
With ECC, and a properly written operating system, the damage can be handled in a more subtle way. Correctable errors are logged for later maintenance. Uncorrectable errors only kill the application they occur in, if the address of the error is in an application's address space. The operating system can keep a list of memory pages that have generated errors, and not allocate those pages for use in the future, sort of like a bad block list on a hard disk.
ECC protection of main memory is distinct from ECC protection of CPU cache memory. They are independent. You can have ECC main memory with or without ECC cache. On PCs, the ECC encoder/decoder for cache is on the CPU chip, the ECC encoder/decoder for main memory is part of the chipset.
I believe ECC is worth having, even if you are not using the computer to run "mission critical" tasks. Memory problems on a computer without parity or ECC can be very difficult to diagnose. The symptoms may look like a flakey operating system or application, not a hardware problem. I had one computer that would only fail when someone ran the FORTRAN compiler. The symptoms looked exactly like a bug in the FORTRAN compiler. It turned out that one of the DRAM chips had a pattern sensitivity problem that was triggered by the image of the FORTRAN compiler. These kinds of problems can be difficult to detect and fix without hardware support. The memory diagnostics in the power-on self-test in the BIOS will detect hard errors, but not more subtle errors.
Scrubbing detects and corrects memory errors that are in memory addresses that are idle. This prevents correctable errors from turning into uncorrectable errors in sections of memory that are infrequently accessed by the CPU.
Anything that prevents this, NAT, DHCP with static DNS, "transparent" proxies, draconian firewalls or usage policies, is bad. Unfortunately, many Internet users are second-class citizens, limited by technology or corporate policy to the status of "information consumers".
You may have given them the right to make inspections or audits when you signed a contract. My local cable company has a clause for this in their service agreement. A software license may also include language that permits audits.
I think I've already seen the indestructible sandwich, in an English pub. I made the mistake of buying one. It tasted like left-over emergency rations from World War II.
In one project that I worked on, the Courier worked much better than the Sportster over impaired international telephone lines. Plus, the Courier had more features, more reliable hardware and better documentation.
$300 isn't excessive for commercial grade equipment. The Courier is a well-designed modem. I've seen people try to save a few bucks by buying a cheap modem and then waste thousands of dollars on trying to make the cheap modem work properly, only to end up tossing the cheap modems and replacing them with Couriers.
That is not true. Early nuclear weapons designs had severe safety problems by modern standards. It took many years of engineering and testing to solve the problems. A Hiroshima type bomb can be made to go critical by immersing it in water. A Nagasaki type bomb can explode with a measurable nuclear yield if the high-explosive lens assembly is detonated by fire or shockwave.